1. Field of the Invention
The present disclosure relates to projectors that irradiate images formed on a small-scale image formation device with illumination light, and through a projection lens magnify and project the images onto a screen.
2. Description of the Background Art
As the light source for projectors that utilize liquid-crystal or mirror-deflection-type digital micro-mirror devices (DMDs) as image-formation means, discharge lamps have been widely employed. Discharge lamps carry with their problems of short lifespan, leading to poor reliability. Projectors utilizing solid-state light sources—semiconductor lasers or light-emitting diodes—as light sources in order to solve these problems have recently been disclosed. FIG. 6 represents a conventional projector employing a solid-state light source and a DMD. Ultraviolet light from a light-emitting diode 1 is incident on a color wheel 2. A reflective film that transmits ultraviolet light and reflects visible light is formed on the color wheel 2, and respective layers of a fluorescent material for red, green and blue are formed on the light-output side of the reflective film, in regions dividing the round disc into three sectors. By the ultraviolet light incident on the color wheel 2, red, green, and blue light is emitted. The emitted light passes through and reflects off a relay lens 3, a reflection mirror 4, and a prism 5, and is incident on the DMD 6. Light modulated by the DMD 6 in accordance with a video signal is magnified and projected through a projection lens 7.